Wireless local area networks (WLANs) have gained broad popularity. The original IEEE 802.11 WLAN standard was designed to enable communications at 1-2 Mbps in a band around 2.4 GHz. More recently, IEEE working groups have defined the 802.11a, 802.11b, 802.11e, 802.11g, 802.11n and other extensions to the original standard, in order to enable higher data rates. In the context of the present patent application and in the claims, the term “802.11” is used to refer collectively to the original IEEE 802.11 standard and all its variants and extensions, unless specifically noted otherwise. WLAN is also sometimes referred to as Wi-Fi®.
WiMAX (Worldwide Interoperability for Microwave Access) is a new technology for wireless packet data communications, which is similar in concept to IEEE 802.11, but has a number of enhancements designed to improve performance and range. The original WiMAX standard, IEEE 802.16, specified WiMAX in the 10-66 GHz range. More recently, IEEE 802.16a added support for the 2-11 GHz range, and IEEE 802.16e (approved as IEEE 802.16-2005) extended WiMAX to mobile applications, using an enhanced orthogonal frequency division multiple access (OFDMA) modulation scheme. In the context of the present patent application and in the claims, the term “802.16” is used to refer collectively to the original IEEE 802.16 standard and all its variants and extensions, unless specifically noted otherwise.
Bluetooth® wireless technology is a short-range communication technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The latest Bluetooth specification, entitled “Specification of the Bluetooth System, Core Version 2.1+Enhanced Data Rate (EDR),” Jul. 26, 2007, defines a uniform structure for a wide range of devices to connect and communicate with each other. This specification, as well as additional information regarding Bluetooth, is available at www.bluetooth.com. In the context of the present patent application and in the claims, the term “Bluetooth Specification” is used to refer collectively to the Version 2.1 specification, to its variants and extensions and to earlier versions of the specification, unless specifically noted otherwise.
Version 1.2 and later versions of the Bluetooth specification define an operational mode called Extended Synchronous Connection-Oriented (eSCO), which forms a point-to-point link between a master and a specific slave. Bluetooth eSCO links offer limited retransmission of packets. If these retransmissions are required they take place in the slots that follow the reserved slots, otherwise the slots may be used for other traffic.
WLAN, WiMAX and Bluetooth systems often operate in adjacent or overlapping frequency bands, and thus may potentially interfere with one another. This interference is particularly severe when WLAN, WiMAX and/or Bluetooth devices are collocated in a single wireless terminal.
Several methods and devices are known in the art for enabling the coexistence of WLAN and Bluetooth communication in the same wireless terminal. For example, Texas Instruments, Inc. (Dallas, Tex.) offers a hardware and software solution that allows users to run Bluetooth and 802.11a/b/g mobile WLAN simultaneously. The software monitors WLAN and Bluetooth traffic patterns and, when both 802.11 and Bluetooth require bandwidth, the software uses multiplexing techniques to allocate the bandwidth for simultaneous functions. The solution is described in a product bulletin entitled “Wireless Performance Optimization Solutions Bluetooth and 802.11 Coexistence,” 2003, which is incorporated herein by reference.
As another example, NXP Semiconductors (Eindhoven, Netherlands) provides another hardware and software solution, which enables Bluetooth and WLAN coexistence using packet transmission arbitration techniques. This solution is described in a white paper entitled “How 802.11b/g WLAN and Bluetooth Can Play,” September, 2005, which is incorporated herein by reference.